text: #   Copyright (c) 2016, Xilinx, Inc.
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  from . import Arduino_DevMode
  from . import ARDUINO_SWCFG_DIOALL
  from . import ARDUINO_DIO_BASEADDR
  from . import ARDUINO_DIO_TRI_OFFSET
  from . import ARDUINO_DIO_DATA_OFFSET
  from . import ARDUINO_CFG_DIO_ALLINPUT
  from . import ARDUINO_CFG_DIO_ALLOUTPUT
  from . import ARDUINO_NUM_ANALOG_PINS
  from . import ARDUINO_NUM_DIGITAL_PINS
  
  
  __author__ = "Yun Rock Qu"
  __copyright__ = "Copyright 2016, Xilinx"
  __email__ = "pynq_support@xilinx.com"
  
  
  class Arduino_IO(Arduino_DevMode):
      """This class controls the Arduino IO pins as inputs or outputs.
      
      Note
      ----
      The parameter 'direction' determines whether the instance is input/output:
      'in'  : receiving input from offchip to onchip. 
      'out' : sending output from onchip to offchip.
      
      Note
      ----
      The index of the Arduino pins:
      upper row, from right to left: {0, 1, ..., 13}. (D0 - D13)
      lower row, from left to right: {14, 15,..., 19}. (A0 - A5)
      
      Attributes
      ----------
      microblaze : Arduino
          Microblaze processor instance used by this module.
      index : int
          The index of the Arduino pin, from 0 to 19.
      direction : str
          Input 'in' or output 'out'.
      
      """
      def __init__(self, mb_info, index, direction): 
          """Return a new instance of a Arduino IO object.
          
          Parameters
          ----------
          mb_info : dict
              A dictionary storing Microblaze information, such as the
              IP name and the reset name.
          index: int
              The index of the Arduino pin, starting from 0.
          direction : str
              Input 'in' or output 'out'.
              
          """
          num_pins = ARDUINO_NUM_ANALOG_PINS + ARDUINO_NUM_DIGITAL_PINS
          if index not in range(num_pins):
              raise ValueError("Valid pin indexes are 0 - {}."
                               .format(num_pins-1))
          if direction not in ['in', 'out']:
              raise ValueError("Direction can only be 'in', or 'out'.")
  
          super().__init__(mb_info, ARDUINO_SWCFG_DIOALL)
          self.index = index
          self.direction = direction
  
          self.microblaze.start()
          if self.index in range(ARDUINO_NUM_DIGITAL_PINS):
              if self.direction == 'in':
                  self.write_cmd(ARDUINO_DIO_BASEADDR +
                                 ARDUINO_DIO_TRI_OFFSET,
                                 ARDUINO_CFG_DIO_ALLINPUT)
              else:
                  self.write_cmd(ARDUINO_DIO_BASEADDR +
                                 ARDUINO_DIO_TRI_OFFSET,
                                 ARDUINO_CFG_DIO_ALLOUTPUT)
          else:
              if self.direction == 'in':
                  self.write_cmd(ARDUINO_AIO_BASEADDR +
                                 ARDUINO_AIO_TRI_OFFSET,
                                 ARDUINO_CFG_AIO_ALLINPUT)
              else:
                  self.write_cmd(ARDUINO_AIO_BASEADDR +
                                 ARDUINO_AIO_TRI_OFFSET,
                                 ARDUINO_CFG_AIO_ALLOUTPUT)
          self.microblaze.load_switch_config()
  
      def write(self, value): 
          """Send the value to the offboard Arduino IO device.
  
          Note
          ----
          Only use this function when direction is 'out'.
          
          Parameters
          ----------
          value : int
              The value to be written to the Arduino IO device.
              
          Returns
          -------
          None
              
          """
          if value not in (0, 1):
              raise ValueError("Arduino IO can only write 0 or 1.")
          if not self.direction == 'out':
              raise ValueError('Arduino IO used as output, declared as input.')
  
          if self.index in range(ARDUINO_NUM_DIGITAL_PINS):
              if value:
                  cur_val = self.read_cmd(ARDUINO_DIO_BASEADDR +
                                          ARDUINO_DIO_DATA_OFFSET)
                  new_val = cur_val | (0x1 << self.index)
                  self.write_cmd(ARDUINO_DIO_BASEADDR +
                                 ARDUINO_DIO_DATA_OFFSET, new_val)
              else:
                  cur_val = self.read_cmd(ARDUINO_DIO_BASEADDR +
                                          ARDUINO_DIO_DATA_OFFSET)
                  new_val = cur_val & (0xffffffff ^ (0x1 << self.index))
                  self.write_cmd(ARDUINO_DIO_BASEADDR +
                                 ARDUINO_DIO_DATA_OFFSET, new_val)
          else:
              if value:
                  cur_val = self.read_cmd(ARDUINO_AIO_BASEADDR +
                                          ARDUINO_AIO_DATA_OFFSET)
                  new_val = cur_val | (0x1 << (
                      self.index-ARDUINO_NUM_DIGITAL_PINS))
                  self.write_cmd(ARDUINO_AIO_BASEADDR +
                                 ARDUINO_AIO_DATA_OFFSET, new_val)
              else:
                  cur_val = self.read_cmd(ARDUINO_AIO_BASEADDR +
                                          ARDUINO_AIO_DATA_OFFSET)
                  new_val = cur_val & (0xffffffff ^ (0x1 << (
                      self.index-ARDUINO_NUM_DIGITAL_PINS)))
                  self.write_cmd(ARDUINO_AIO_BASEADDR +
                                 ARDUINO_AIO_DATA_OFFSET, new_val)
  
      def read(self):
          """Receive the value from the offboard Arduino IO device.
  
          Note
          ----
          Only use this function when direction is 'in'.
          
          Returns
          -------
          int
              The data (0 or 1) on the specified Arduino IO pin.
          
          """  
          if not self.direction == 'in':
              raise ValueError('Arduino IO used as input, declared as output.')
          
          if self.index in range(ARDUINO_NUM_DIGITAL_PINS):
              raw_value = self.read_cmd(ARDUINO_DIO_BASEADDR +
                                        ARDUINO_DIO_DATA_OFFSET)
              return (raw_value >> self.index) & 0x1
          else:
              raw_value = self.read_cmd(ARDUINO_AIO_BASEADDR +
                                        ARDUINO_AIO_DATA_OFFSET)
              return (raw_value >> (self.index-ARDUINO_NUM_DIGITAL_PINS)) & 0x1
  
      def _state(self):
          """Retrieve the current state of the Arduino IO.
          
          This function is usually used for debug purpose. Users should still
          rely on read() or write() to get/put a value.
          
          Returns
          -------
          int
              The data (0 or 1) on the specified Arduino IO pin.
          
          """
          if self.index in range(ARDUINO_NUM_DIGITAL_PINS):
              raw_value = self.read_cmd(ARDUINO_DIO_BASEADDR +
                                        ARDUINO_DIO_DATA_OFFSET)
              return (raw_value >> self.index) & 0x1
          else:
              raw_value = self.read_cmd(ARDUINO_AIO_BASEADDR +
                                        ARDUINO_AIO_DATA_OFFSET)
              return (raw_value >> (self.index-ARDUINO_NUM_DIGITAL_PINS)) & 0x1
  